Method and apparatus for providing closed ventilation circuit for automotive crankcases



Aug. 11, 1964 c, c. ANTHEs 3,144,011

METHOD AND APPARATUS FOR PROVIDING CLOSED VENTILATION CIRCUIT FOR AUTOMOTIVE CRANKCASES 4 Sheets-Sheet 1 Filed Nov- 1, 1961 Im 2 l ommmw K40 o: oo. om om 2. ow on 9. on 3 9 o 6585a 5-26 6 5m 3 I w v Q5816 6&3: 5m: .1

W50 "MO'IJ INVENTOR. CLIFFORD c. ANTHES w A. NM NS.

.4 T TORNE V Im s cummm E40 7 OO- Om Om Oh 8 On Qv On ON 0- O 4 Sheets-Sheet 2 v QM C- ANTHES c/ oi nmkomaxm 2 DQ hmmIQI CIRCUIT FOR AUTOMOTIVE CRANKCASES Aug. 11, 1964 METHOD AND APPARATUS FOR PROVIDING CLOSED VENTILATION Filed Nov. 1, 1961 QNN lNVEN'I OR. CLIFFORD C. ANTHES ATTORNEY Aug. 11, 1964 c. c. ANTHES 3,144,011

METHOD AND APPARATUS FOR PROVIDING CLOSED VENTILATION CIRCUIT FOR AUTOMOTIVE CRANKCASES 4 Sheets-Sheet 3 Filed Nov. 1, 1961 INVENTOR.

CLlFFORD C. ANTHES A TTORNE Y Aug. 11, 1964 c c ANTHES 3,144,011

METHOD AND APPARATUS PROVIDING CLOSED VENTILATION CIRCUIT FOR AUTOMOTIVE CRANKCASES 4 Sheets-Sheet 4 Filed Nov. 1, 1961 FIG. 6 FIG. 7

INVENTOR.

L CLIFFORD c. ANTHES BY A T TORNfY United States Patent METHOD AND APPARATUS FOR PROVIDING CLOSED VENTILATION CmCUIT FOR AUTO- MOTIVE CRANKCASES Clifford C. Anthes, Union, N.J., assignor to Union Carbide Corporation, a corporation of New York Filed Nov. 1, 1961. Ser. No. 149,250 5 Claims. (Cl. 123119) This invention relates to prevention of pollution of the atmosphere by exhaust products from the crankcase of automotive internal combustion engines.

The problem of contamination of the air by the exhaust products of automotive internal combustion engines is receiving ever increasing attention because the amount of contaminants in the air, especially in urban areas, has become so great as to be injurious to the public health.

These contaminants in the exhaust products of internal combustion engines are made up of partially burned fuel gases and other harmful products. They are discharged into the air through the exhaust system of the engine and also as gases blown past the pistons in the cylinders of the engine into the crankcase. These contaminant-con taining blowby gases are then discharged from the crankcase into the air through the oil fill cap or other secondary crankcase vent tube. The amount of such gases blown by the pistons into the crankcase and thence into the air has been reported to be responsible for up to 50 percent of the total amount of contamination discharged into the air by the engines of automobiles, trucks and buses.

It has been proposed to rid the crankcase of such blowby gases before they are discharged into the air by recycling these gases back into the engine where they can be more fully combusted. A common method of removing blowby gases from the crankcase uses a valved'conduit connecting the crankcase and the intake manifold or carburetor system of the engine. The vacuum in the intake manifold and carburetor system (called herein the induction system) resulting from the induction or suction stroke of the engine draws the gases from the crankcase into the engine for further combustion. The degree of vacuum in the intake manifold and carburetor system varies with the speed and work load on the engine. The amount of contaminant-containing gases blown by the pistons also varies with the speed and work load on the engine but in an inverse relationship to the variation in the degree of vacuum. Flow regulating valves have been used in an only partially successful attempt to use the induction system vacuum to draw gases from the crankcase and thereby prevent the pollution of the air by these blowby gases.

In the drawings:

FIG. 1 is a graphical representation of the amount of contaminant-containing blowby gases blown past the pistons of an internal combustion engine as this amount varies with the speed of the vehicle;

FIG. 2 is a graphical representation of the intake manifold vacuum showing the change in manifold vacuum with increasing vehicle speed;

FIG. 3 is a graphical representation of the actual blowby gas flow from an engine into the crankcase (dashed line) with the gas flow characteristics of a prior art ventilating system (solid line) and the ventilating system of this invention (dash-dot line);

FIG. 4 is a phantom view showing a cross section of an internal combustion engine with a. crankcase ventilating conduitand flow regulator of this invention connected to the carburetor air hood;

FIG. 5 is an elevational section of the flow regulator of FIG. 4;

FIG. 6 is a phantom view showing a cross section of an internal combustion engine with a crankcase ventilating 3,144,011 Patented Aug. 11, 1964 conduit and flow regulator of this invention connected to the intake manifold of the engine;

FIG. 7 is a elevational section of the flow regulator of FIG. 6.

In FIG. 1 it is seen that the amount of blowby gases blown into the crankcase increases with increasing vehicle speed or work load on the engine. The amount of blowby gases is at its lowest when the vehicle speed is zero, that is, when the engine is idling. The amount of blowby gases increases rapidly with increasing vehicle speed. The amount of blowby gas flow also increases with the work load on the engine so that the amount of blowby gases rwultingfrom hill climbing or rapid acceleration can be as high as if the vehicle were operating at a speed of 60 to miles per hour or more.

In FIG. 2 it is shown thatthe intake manifold vacuum varies inversely with the vehicle speed, i.e., as the vehicle speed or work load increases, the vacuum in the intake manifold decreases, as does the vacuum in the carburetor system. Since some crankcase ventilating systems use the vacuum in the induction system to draw gases from the crankcase, the following situation arisesthat the vacuum in the intake manifold (and the gas drawing power) is highest when the rate of flow of blowby gases is the lowest. This relationship is shown in FIG. 3 in terms of the performance of a, prior art crankcase ventilating system and the performance of the ventilating system of this invention. In the graph the intake manifold vacuum is seen to decrease as the average blowby gas volume (dashed line) increases. The solid line represents the actual performance of a prior art crankcase ventilator of the type using a spring loaded check valve in the conduit connecting the crankcase and intake manifold. The check valve is opened by the pressure differential resulting from the addition of a slight positive pressure in the crankcase and a high intake manifold negative pressure at low engine speeds at which'time the valve allows a largevolume of gases to enter the intake manifold. It is seen that the valve allows a considerably larger volume of gases to be drawn from the crankcase at low speeds (solid line) than the volume of blowby gases actually being blown into the crankcase (dashed line). This can be detrimental to efiicient engine performance and to the lubricating system.

The large volume of gases drawn through the prior art valve by the high manifold vacuum at idling of the engine is made up of the small amount of blowby gas and a larger amount of air drawn into the crankcase from the oil fill cap or other vent tubes. While it may be desirable to draw a small amount of air from the oil fill cap into the crankcase to purge the crankcase of the corrosive blowby gases, it is not desirable-to draw such large amounts of air as shown in the graph as this would tend to upset the fuel-air ratio fed to the engine.

On the other hand when the engine is operating at high speed (far right side of the graph) and the manifold vacuum decreases to near atmospheric pressure, the valve draws a .lesser volume of gases from the crankcase than is being blown into the crankcase from the engine. The result is that pollution of the atmosphere takes place through the oil fill cap despite the presence of the conduit from the crankcase to the intake manifold.

It is the object of this invention, therefore, to provide a crankcase ventilating and recycling system which does not allow the escape of contaminant-containing blowby gaseslinto the air under any of the varying conditions of car speed or workload on the engine.

It is another object of this invention to provide a crankcase ventilating and recycling system which does not overly disrupt engine performance by discharging into the intake manifold or drawing into the crankcase any unnecessary amounts of air.

Other aims and advantages of the invention will be apparent from the following description and the appended claims.

In accordance with these objects an invention s provided for use in cranckcase ventilating systems wherein a conduit is established between the air space over the oil in the crankcase and the induction system of an internal combustioen engine and wherein the vacuums in the induction system and the pressures and flow rates in the crankcase of gases blown past the piston rings into the crankcase are used to cause gases including blowby gases to flow into the induction system for recombustion, said vacuums, pressures and flow rates varying with the work output of the engine, the improvement comprising continuously regulating the flow of gases from the crankcase to the induction system to a volume of gases substantially equal to the volume of gases blown into the crankcase from the engine by maintaining in the air space over the oil in the crankcase a substantially unvarying preselected pressure.

As previously discussed the problem of air pollution by crankcase gases has been partially solved by venting the blowby gases from the crankcase and feeding or recycling these gases into the induction system of the engine, either into the carburetor system or directly into the intake manifold. This, in effect, provides a closed system for the crankcase ventilating circuit, compared to older arrangements where such gases were discharged into the atmosphere through the oil fill cap or secondary crankcase vent tubes. It has been found, however, that this venting of the crankcase should be accomplished without varying the pressure in the crankcase any appreciable amount over the full range of vehicle operating speeds and work loads. The direct result of operating the crankcase venting system so that the pressure in the crankcase is not appreciably varied is that the volume of gases drawn from the crankcase is substantially equal to the volume of gases blown past the piston rings into the crankcase over the full range of vehicle operating speeds and work loads.

It is, of course, necessary to draw all of the blowby gases from the crankcase at all engine work loads so that an effective prevention of atmospheric pollution can be accomplished. In other words, if the volume flow of blowby gases through the feed back (or recycling) system is less than the volume flow of blowby gases into the crankcase, then there will be a tendency for the pressure of such gases in the crankcase to increase and, thus, for the blowby gases to be discharged into the atmosphere through the oil fill cap or the secondary vent tube. On the other hand, if the volume flow of blowby gases through the feed back conduit between the crankcase and engine induction system is greater than the volume flow of blowby gases into the crankcase, then there will be a tendency for a low pressure area to develop in the crankcase and for atmospheric air to be pulled or sucked into the crankcase through the oil fill cap, secondary vent tubes, or other possible leakage points. The results of either condition can be undesirable. In the first instance, the protection against atmospheric pollution is incomplete. In the second instance, more air and gases are being fed back into the induction system of the engine than is necessary, thus, increasing any tendency for these entering gases to upset the gas-air mixture ratio being fed to the engine cylinders.

Although, as stated, it is undesirable to cause excessive amounts of air to be drawn into the crankcase and thence to the engine cylinders, it is desirable to draw into the crankcase through the oil fill cap a small amount of air for purging of the crankcase. A small amount of fresh air mixed with the blowby gases will ensure removal from the crankcase of these blowby vapors. In FIG. 3 the dash-dot line shows the performance of the ventilating system of this invention where a volume of gas is drawn from the crankcase which is substantially equal to the amount of blowby gases blown into the crankcase. This amount includes a small additional amount of fresh air drawn in through the oil fill cap. (The displacement of the dash-dot line over the blowby gas flow is arbitrarily selected here.) If the exact volume of blowby gases blown into the crankcase is to be removed, then the preselected pressure to be maintained in the crankcase is atmospheric pressure, whereby no air will flow in through the oil fill cap. If, however, a small crankcase-purging amount of air is to be drawn into the crankcase from the oil fill cap and passed into the engine, then a slight negative pressure is the preselected pressure to be maintained in the crankcase. It is considered that such a volume of purging air may be drawn into the crankcase and passed into the engine without disturbing the engine performance as corresponds to a crankcase vacuum of up to 5 inches water column pressure of atmospheric. It is to be understood that the amount of air drawn into the crankcase can be regulated by an orifice in an otherwise sealed crankcase chamber, the orifice diameter and crankcase negative pressure being so selected as to draw into the crankcase the proper amount of air.

The preselected crankcase pressure can also be maintained slightly more positive than atmospheric, in which case there would be no drawing in of air from the oil fill cap, provided the pressure is not so positive as to cause gases to exit through the oil fill cap. Such pressures might be up to +5 inches water column. In this case the dash-dot line would be parallel but below the dashed line in FIG. 3.

It is also possible to completely seal the crankcase except for the vent to the flow regulator and induction system. The oil fill cap would then be of an air tight type.

By maintaining a substantially unvarying preselected pressure is meant that the pressure should be kept substantially constant despite the changes in manifold vacuum tending to act through the conduit, and the changes in blowby gas flow into the crankcase, each varying with the engine speed and Work load. Small variations are allowable provided the intended gas flow from the crankcase is maintained. 1

In FIG. 4 a flow regulator for maintaining a substantially unvarying preselected pressure in the crankcase chamber is shown in the conduit line from the crankcase to the carburetor of the engine. The crankcase is shown at 11 with a vent hole 12 in the valve cover. The vent hole to the crankcase is shown here in the valve cover for convenience, a passage from the vent hole to the air space over the oil in the crankcase being assumed. A conduit or other form of gas passage 17 connects the crankcase 11 with the carburetor 19. A flow regulator 14 is shown in this line and comprises a casing, a flexible diaphragm clamped within said casing dividing said casing into a first and a second chamber, a gas inlet into said first chamber for connection to the crankcase end of the conduit, a gas outlet from said first chamber for connection to the carburetor end of said conduit, a valve between said inlet and outlet actuated by flexure of said flexible diaphragm, and a spring within said first chamber between the diaphragm'and the casing wall, said spring biasing the diaphragm to open the valve between the inlet and outlet for inlet gas pressures equal to and more positive than a preselected inlet gas pressure.

More specifically the carburetor end of the conduit is connected to the carburetor upstream of the filter in the air hood 18 so that the filter acts as a flash arrester. The flow regulaor 14 is shown with its inlet 15 connected to the crankcase vent 12 and its outlet 16 connected to the carburetor. V

The flow regulator, as shown in FIG. 5, has a body 20, containing inlet connection 15 and outlet connection 16, a cap 23 and flexible diaphragm 24, shown in this embodiment sealingly clamped at its outer periphery between the valve body 20 and cap 23 forming thereby two chambers, a first chamber in which are located the inlet and outlet, and a second chamber which is vented to the atmosphere.

A diaphragm plate and valve seat 25 is shown fastened to the diaphragm 24 by rivet 26. A valve nozzle 27 bears against the diaphragm plate and valve seat 25. Vent hole 28 in the cap 23 provides for atmospheric pressure loading of diaphragm 24. Valve opening spring 29 is a relatively light spring having a force equal to the desired crankcase pressure times theefiective diaphragm area. As discussed above the flow control valve operates to draw a volume of gases from the crankcase substantially equal to the volume of blowby gases blown into the crank case by maintaining in the. crankcase a substantially unvarying preselected pressure.

The preselected pressure to be maintained in the crankcase may be inches, but is usually :Zinches water column pressure. In this instance, the spring is selected to have a force equal and opposite to a desired preselected crankcase pressure of -0.3, inch water column pressure times the effective diaphragm area. This means that the valve is normally open (shown closed in the drawing for convenience) for any pressure more positive than --0.3 inch water column pressure in the crankcase causes the valve to open. When the pressure in the crankcase drops. to -03 inch or lower, the valves close. However, there is always some flow of blowby gases when the engine is running and these gases have a tendency to cause the pressure in the crankcase to rise over --0.3 inch water column pressure causing the valve to open by lifting the diaphragm plate 24 off the nozzle 27 permitting the blowby gases to flow out of the crankcase, through the valve and conduit and into the air hood 18 bringing the pressure in the crankcase back to -0.3 inch. Since the pressure in the air hood ranges between only -01 inch to 2.0 inch water column pressure (compared to a variation of 0 inch mercury to about 20 inches mercury or more in the intake manifold) and this small pressure acts over such a small relative area of the diaphragm, it can be ignored as far as the operation of the valve is concerned.

Thus, it may be seen that the extent of the opening of the valve is controlled by the pressure in the crankcase and is, therefore, directly proportional to the rate of blowby gas flow entering the crankcase. In this manner, the volume flow of blowby gases through the flow regulator from the crankcase, regardless of car speed, will be equal to the volume flow of blowby gases past the engine pistons into the crankcase.

Since the range of vacuum in the air hood of the carburetor is narrow, only up to about 2.0 inches water column pressure, there is only a small pressure drop available across the flow regulator and conduit connected to the crankcase. It may be desirable to use the high range of vacuums available in the intake manifold to provide a larger available pressure drop. In FIG. 6 an arangement is shown wherein the blowby gases are fed directly into the intake manifold of the engine. The crankcase 39 is shown with a vent 31 to which is connected the inlet port 32 of a flow regulator 33. The outlet 34 of the flow regulator is connected to a conduit.35 leading into the intake manifold 36 of the engine. As shown in FIG. 7 flow regulator 33 comprises a body 37 containing inlet connection 32 and outlet connection 34, and a cap 38 which is vented to the atmosphere by a port 39. Flexible diaphragm 40 is shown in this embodiment to be sealingly clamped between .the valve body 37 and cap 38 forming two chambers, the first chamber in which are located the inlet and outlets, and the second chamber which is vented to the atmosphere. A diaphragm plate 41 is attached to the flexible diaphragm 40. The valve opening spring is again selected to hold the valve open when the crankcase pressure is 0.3 inch water column pressure or more positive. Since the outlet of the regulator is exposed to intake manifold pressure variations of from O to --20 inches of mercury, the regulator must be balanced against such intake manifold variations. This is accomplished by a valve in the first chamber between the inlet and outlet, said valve having a stationary member communicating with said outlet and having ports therein for passage of gas from said first chamber into said outlet, and a movable valve closing element for closing the ports in the stationary member to the passage therethrough of gas, a valve stem connecting said movable element and said flexible diaphragm for actuating said valve closing element in response to flexure of the diaphragm, said movable element having twoparallel faces of substantially the same surface area, said faces each exposed to the pressures in the outlet connection, the force of the manifold vacuum on one face tending to close and on the other face tending to open the ports, whereby said valve closing member is substantially irresponsive to the said outlet pressures and responsive only to diaphragm flexure through the connecting valve stem. The valve shown here is balanced by ported valve member 43 which is a cylinder closed at one end by a cap 44 and open at the other end forming the regulator outlet connection 34. The member 43 has valve ports 45 to provide for the passage of gas through the regulator 33 when closing element 46 is in the open or raised position (as shown). Valve closing element 46 slides inside the cylindrical valve member 43. The valve closing element 46 is attached to the diaphragm 40 by connecting stem or rod 47 and slides within member 43 in response to movement of the diaphragm. The valve closing element 46 has ports 48 whereby the pressure in the inlet manifold, acting over the equal areas on either side of valve closing element 46, will have no effect on the movement of the valve closing element 46 or diaphragm 4. The small area taken up by the stem 47 is negligible.

In operation the flow regulator is normally open to the flow of blowby gases from the crankcase as long as the crankcase pressure is 0.3 inch water column pressure or more positive. The pressure in the crankcase acts on the diaphragm 40 controlling the movement of the valve closing element 46. Thus, the extent of valve opening is directly proportional to the rate of blowby gas flow entering the crankcase and, hence, the volume flow of blowby gases through the flow regulator 33 from the crankcase, regardless of the car speed or work load, will be equal to the volume flow of blowby gases past the crankcase into the crankcase. A small amount of purging air is also drawn into the crankcase because the preselected pressure is 0.3 inch. Referring to FIG. 3 the prior art crankcase ventilating valve is seen to draw a larger volume of gases from the crankcase than is being blown into the crankcase when the engine is at low s'peed; while at high engine loads when the intake manifold vacuum is low, the volume of gases taken from the crankcase is less than the volume of blowby gases blown into the crankcase. With the valves of this invention, however, the. volume of gases taken from the crankcase will substantially follow the dashed line indicating the actual amount of gases blown into the crankcase (plus purging air as desired) thereby achieving the improvements in pollution control and engine efficiency already discussed.

Since the conduit and flow regulator may provide an opening from the intake manifold to the crankcase, it may be necessary to position a flash arrester in this line to prevent the passage of a flame to the crankcase. A suitable flash arrester could consist of a chamber containing a bed of steel shot between the outlet of the flow regulator and the intake manifold.

What is claimed is:

1. In the method of operating an internal combusting engine wherein exhaust products are blown by the pistons in the cylinders of the engine into the crankcase and a conduit is established between the air space above the oil in the crankcase and the induction system of the engine, and wherein the vacuum in the induction system and the pressures and flow rates in the crankcase of blowby gases in the crankcase are used to cause gases to flow from the crankcase into the induction system for recombustion, said vacuums, pressures and flow rates varying with the work output of the engine, the improvement comprising continuously regulating the flow of gases from the crankcase to the induction system to a volume of gases substantially equal to the volume of gases blown into the crankcase from the engine by maintainingin the crankcase a substantially unvarying preselected pressure.

2. A crankcase ventilating system comprising, in combination, an internal combustion engine having a crankcase and a carburetor with an air hood, a flow control regulator in a crankcase ventilator conduit connecting the crankcase and the carburetor air hood, said flow control regulator comprising a casing, a flexible diaphragm clamped within said casing dividing said easing into a first and a second chamber, a vent hole in the casing wall above the second chamber to provide for atmospheric loading of the diaphragm, a gas inlet into said first chamber connected to the crankcase end of the conduit, a gas outlet from said first chamber connected to the carburetor end of said conduit, a valve between said inlet and outlet actuated by flexure of said flexible diaphragm, and a spring within said first chamber between the diaphragm and the casing wall, said spring biasing the diaphragm to open the valve between the inlet and outlet for inlet gas pressures equal to and more positive than a preselected inlet gas pressure.

3. A crankcase ventilating system comprising, in combination, an internal combustion engine having a crankcase and a carburetor, a flow control regulator in a crankcase ventilator conduit connecting the crankcase and the carburetor, said fiow control regulator comprising a casing, a flexible diaphragm clamped within said casing dividing said casing into a first and a second chamber, a vent hole in the casing wall above the second chamber to provide for atmospheric loading of the diaphragm, a gas inlet into said first chamber connected to the crankcase end of the conduit, a gas outlet from said first chamber connected to the carburetor end of said conduit, a stationary valve nozzle communicating with said gas outlet, a plate between said nozzle and said diaphragm, said plate attached to said diaphragm and forming a valve seat mov able to and from the stationary valve nozzle on flexure of the diaphragm, and a spring in said first chamber between said diaphragm and said casing wall for biasing said diaphragm and plate away from the valve nozzle to open said valve for inlet gas pressures equal to and more positive than a preselected inlet gas pressure. 1

4. A flow control regulator for use in a crankcase ventilator conduit connecting the crankcase and the intake manifold of an internal combustion engine, said flow control regulator comprising a casing, a flexible diaphragm clamped within said casing dividing said casing into a first chamber and a second chamber, a vent hole in the casing wall above the second chamber to provide for atmospheric loading of the diaphragm, a gas inlet into said first chamber for connection to the crankcase end of said conduit, a gas outlet from said first chamber for connection to said intake manifold end of said conduit, a valve in said first chamber between said inlet and outlet, said valve having a stationary member communicating with said outlet and having ports therein for passage of gas from said first chamber into said outlet, and a movable valve closing element for closing the ports in the stationary element to the passage therethrough of gas, a valve stem connecting said movable element and said flexible diaphragm for actuating said valve closing element in response to flexure of the diaphragm, said movable element having two parallel faces of substantially the same surface area, said faces each exposed to the pressures in the outlet connection, the force of the manifold vacuum on one face tending to close and the other face tending to open the ports, whereby said valve closing member is substantially irresponsive to the said outlet pressures and responsive only to diaphragm flexure through the connecting valve stem, and a spring in the first chamber between said diaphragm and said casing for biasing said diaphragm and attached valve stem to position the movable valve closing element away from the ports in the stationary valve element and thereby open the valve for inlet gas pressures equal to and more positive than a preselected inlet gas pressure.

5. A flow control regulator for use in a crankcase ventilator conduit connecting the crankcase and the intake manifold of an internal combustion engine, said flow control regulator comprising a casing, a flexible diaphragm clamped within said casing dividing said casing into a first chamber and a second chamber, a vent hole in the casing wall above the second chamber to provide for atmospheric loading of the diaphragm, a gas inlet into said first chamber for connection to the crankcase end of said conduit, a gas outlet from said first chamber for connection to the intake manifold end of said conduit, a valve in said first chamber having a stationary hollow member connected to the walls of the regulator casing and having one end closed and the opposite end open, said open end communicating with the outlet connection, said hollow member having ports in its longitudinal walls providing passage for gases from said first chamber into the hollow member and out into said outlet connection, a movable valve closing element slidably postioned within said stationary hollow member, a valve stem attached to the flexible diaphragm and slidably passing through a hole in closed end of said stationary hollow member and connected to the movable valve closing element for actuating said movable valve closing element to open and close the ports in the stationary hollow member in response to fiexure of said diaphragm, said movable element having two parallel faces of substantially the same surface area and a gas passage in said element providing communication between the face open to the outlet and the space between'the other face and the walls of the closed end of the stationary hollow member whereby each of said faces is exposed to the gas pressure in the outlet connection and aid valve closing member is substantially irresponsive to said outlet pressures and responsive only to diaphragm fiexure through the connecting valve stem, and a spring in said first chamber between said regulator casing wall and said flexible diaphragm for biasing said diaphragm and attached valve stem to position the valve closing element away from the ports in the stationary hollow member and thereby open the valve for inlet gas pressures equal to and more positive than a preselected inlet gas pressure. 

1. IN THE METHOD OF OPERATING AN INTERNAL COMBUSTING ENGINE WHEREIN EXHAUST PRODUCTS ARE BLOWN BY THE PISTONS IN THE CYLINDERS OF THE ENGINE INTO THE CRANKCASE AND A CONDUIT IS ESTABLISHED BETWEEN THE AIR SPACE ABOVE THE OIL IN THE CRANKCASE AND THE INDUCTION SYSTEM OF THE ENGINE, AND WHEREIN THE VACUUM IN THE INDUCTION SYSTEM AND THE PRESSURES AND FLOW RATES IN THE CRANKCASE OF BLOWBY GASES IN THE CRANKCASE ARE USED TO CAUSE GASES TO FLOW FROM THE CRANKCASE INTO THE INDUCTION SYSTEM FOR RECOMBUSTION, SAID VACUUMS, PRESSURES AND FLOW RATES VARYING WITH THE WORK OUTPUT OF THE ENGINE, THE IMPROVEMENT COMPRISING CONTINUOUSLY REGULATING THE FLOW OF GASES FROM THE CRANKCASE TO THE INDUCTION SYSTEM TO A VOLUME OF GASES SUBSTANTIALLY EQUAL TO THE VOLUME OF GASES BLOWN INTO THE CRANKCASE FROM THE ENGINE BY MAINTAINING IN THE CRANKCASE A SUBSTANTIALLY UNVARYING PRESELECTED PRESSURE. 